Coil form with embedded terminals



June 23, 1970 R. H. HlLGERS COIL FORM WITH EMBEDDED TERMINALS Filed Aug. 30, 1968 R 5 E 2 m T J H m A R T S 6 2 G El R E D E E F m n/ IT l/W. .l i R E 2 D D 2 L U f O R T M X E ZIT FIGZ I llllll INVENTOR:

RAYMOND H. HILGERS United .States Patent O 3,517,365 COIL FORM WITH EMBEDDED TERMINALS Raymond H. Hilgers, Wauconda, Ill., assigner to Resinite Corporation, Wheeling, Ill., a corporation of Illinois Filed Aug. 30, 1968, Ser. No. 756,563 Int. Cl. H011 15/10, 27/30 U.S. Cl. 336-208 2 Claims ABSTRACT OF THE DISCLOSURE A plastic coil form having a flange in which connector wires are embedded at the time of fabrication, the manufacture being achieved through an openable mold wherein the wires are fed in perpendicular to the parting line and in which the wires are severed to provide the discrete connector wire lengths just prior to full closure of the mold parts.

BACKGROUND AND SUMMARY OF THE INVENTION In the electrical art, it has been the practice to equip the inductance-providing coil forms with lugs in order to make connections, i.e., tie points, between the relatively iine wire wound on the coil form and the heavier conductors employed to integrate the inductance into an electrical circuit. Many coil forms are quite small and it is manifestly difficult to equip them With suitable lugs. Millions of coil forms are used each year in the manufacture of electronic gear so that cost considerations are significant.

The coil forms often are equipped with tuning coresthreaded cylinders of powered iron employed to develop the desired inductance. In any case, maintaining the desired value of inductance is important and any loosely connected part or wire can frustrate this--as in bobbins, for example, which have flanges and fixed cores.

I have overcome the drawbacks characteristic of the prior art and have achieved superior stability in, the wire connection means associated with coil forms through the use of novel procedures and equipment in the coil form manufacture, resulting in a coil form itself characterized by novel structure. In brief, I advance a plurality of wires (for each coil form) along generally parallel paths into a two-part mold and with the parting line of the mold being perpendicular to the paths of advance of the wires. As the mold parts close, the ends of the wires are severed to provide discrete lengths within the mold cavity so that most effective integration of the wire connectors with the coil form is achieved, the fluid plastic material flowing in and around the wire parts.

The invention is described in conjunction with an illustrative embodiment in the accompanying drawing, in which- FIG. l is a schematic diagram of apparatus employed to practice the invention;

FIG. 2 is a top plan View of the mold portion of FIG. 1 such as would be seen along the sight line 2-2 of FIG. l;

FIG. 3 is a perspective view of a coil form made in the apparatus seen in the preceding views;

FIG. 4 is a horizontal sectional view taken through the mold of FIG. 2 and essentially in a plane passing through the feed wires of FIG. l; and

FIG. 5 is a vertical sectional view taken along the line 5--5 of FIG. 4.

In the illustration given and with reference to FIG. 3, the numeral designates generally a coil form advantageously manufactured in accordance with the teachings of this invention. It will be seen that the coil form includes a relatively elongated tubular portion 11 and a pair np ICC of flanges 12 and 12a spaced axially along the length of the tubular portion 11. Each flange 12 and 12a is equipped with a pair of tie-in wires as at 13 and 14 relative to the flange 12 and 15 and 16 relative to the flange 12a. The wires 13-16 are so oriented as to have their lengths perpendicular to the axis of the tubular portion 11. The interior of the tubular portion 11 is equipped with a plurality of axially extending ribs 17 which provide advantageous support for a tuning core (not shown). In the utilization of the coil form 10, wire may be wound on the portions 11a and 11b to provide the inductance necessary for various electrical uses.

To produce the coil form of FIG. 3, the apparatus depicted schematically in FIG. l may be employed. The heart of the apparatus is the mold (so designated) and further identied with the numeral 18. The mold 18 is constructed of two parts 19 and 20 (best seen in FIG. 2). The plastic material for the coil form is provided by an extruder 21 coupled through a conduit 22 to an injection orilce 23 (sete FIG. 2). Wire for the coil form is provided from reels 24 (see FIG. l). The wires pass through a straightener 25 and a feeder 26 to provi-de a plurality of wires indicated as at 27 in FIG. 1 and as at 27a and 27h in FIGS. 2 and 4. In FIG. 5, the wires 27a and 27e are identiiied, the wire 27c lying immediately under the wire 27a in FIGS. 2 and 4.

The lmold halves of parts 19 and 20` mate along a parting line (or plane) which is partially indicated by a dotdash line and designated 28 in FIG. 4. Each mold part 19 and 20 is recessed in a portion confronting the parting line to provide a mold cavity 29. Positioned within the mold cavity 29 is a core pin 30 employed to develop the hollow configuration of the tubular portion 11. Fluid plastic material is introduced into the injection orifice 23 and flows into the cavity 29 around the core pin 30', the cavity being suitably contoured to develop flange-providing recesses at at 31 and 32. The core pin 30 is carried by a side acting block 33 which is retracted to the position 33 (see FIG. 2) as the mold halves 19 and 20 are separated. This retracts the core pin 30 to the position designated 30' in FIG. 2 to permit ejection of the completed coil form. Suitable mechanism in the form of cam means (not shown) are provided to open the mold and translate the block 33. For example, a cam follower 34 is provided which actuates the block 33 to follow a path indicated by the cam track 35 (still referring to FIG. 2).

Prior to the closing of the mold halves 19 and 20` at the beginning of a molding cycle, the wires 27 are fed into the mold by the feeder 26. As such, they pass through rst and second blocks 36 and '37 provided as part of the mold half 20. The wires 27 extend through the mold cavity 29 into aligned passages as at 38 and 39 in the other mold half 19. It will be appreciated that the rst and second blocks 36 and 37 are equipped with bores or passages which are sized just to pass the wires 27. The second block 37 is slidably mounted within the mold half 20 and is urged by a compression spring 42 to a position wherein its wire passages 40 are aligned with the wire passages 41 of the 4first block 36. The block 37, for this purpose, is provided as part of a larger assembly 43 equipped adjacent its right end (as seen in FIG. 5) with a beveled surface 44. Reciprocably mounted within a recess 20a in the mold half 20 (see FIG. 5) is an actuator member 45. When the lmold halves are spaced apart, the spring 42 urges the assembly 43 to the right and the member 45 downwardly to the position designated 45. As the mold halves close and the confronting faces of the parts 19 and 20 come into contact, the member 45 is moved upwardly which in turn moves the assembly 43 to the left to shear the wires 27. The sheared condition can be seen in FIG. 5 because of the offset of bores 40 and 41. This occurs just at the moment of mold closure and it will be appreciated that only a very small degree of movement is required. For example, suitable wire for making tie-ins is number 20 AWG which has a diameter of 0.032. The blocks 36 and 37 in their confronting faces are machined to provide a ne sliding contact and this, along with the relatively close iit between the wires 27 and the passages 40 and 41 preclude any leakage of uid plastic material out of the mold cavity 29. The same control of tolerance is characteristic of the wire passages 38 and 39 in the mold half 19.

Communicating with the Wire passages 38 and 39 are ejector pins 46 and 47. These pins, along with others not shown, are actuated by a knock-out plate 48 (see FIG. 2) which in turn is moved inwardly by the mold opening mechanism to thereby punch the now completed coil from the ymold cavity 29. The cavity 29 in the area designated 49 in FIG. 4 is tapered so as to facilitate the entry of the wires 27 into the passages 38 and 39, this being reflected by conical projections 50 (see FIG. 3) about the wire segments 13-16.

While in the foregoing specification a detailed description of the invention has been set down for the purpose of illustration, many variations of the details herein given may be made by those skilled in the art without departing from the spirit and scope of the invention.

I claim:

1. A coil form or the like comprising a unitary plastic generally elongated tubular body equipped with integral flange means extending all around said body, at least one solid wire embedded in said flange means and extending therebeyond on opposite sides of said flange means and therefore extending beyond'opposite sides of said body, the plastic material immediately adjacent said wire conforming exactly thereabout, said wire having a substantially uniform cross section along its length with said wire length being generally perpendicular to said elongated tubular body.

2. The coil form of claim 1 in which said ange means includes a pair of flanges spaced apart axially of said body, and a plurality of wires extending through each of said anges.

References Cited UNITED STATES PATENTS 1,698,608 1/1929 Piper 336-208 1,704,151 3/1929 Simpson 336-192 1,984,036 12/1934 Schwartzmann.

2,899,655 8/1959 Forte 336-198 2,942,333 6/1960 Mason 336-136 X 3,281,744 10/1966 Melanson 336-208 X 3,332,049 7/1967 Hisano 336-192 X 3,359,395 12/1967 Bruce 336-208 X 3,368,177 2/1968 Hilgers 336-208 ELLIOTT A. GOLDB-ERG, Primary Examiner U.S. Cl. X.R. 

